cnn is taking a closer look at the dig. >> reporter: what happened to jimmy hoffa? the notorious one-time teamster union's boss with ties to organized crime disappeared in 1975. now, police plan to drill under the driveway of this suburban detroit home. after receiving a tip from a man who said he'd seen a body being buried here around the time hoffa went missing. initial testing shows there is something underneath the concrete. friday morning, police will take a core sample from the soil there and test it for human remains. >> we do believe that he may have seen a body and as a result we did the ground penetrating radar and we're going to take it to the next step and check for human remains and if that does, in fact, happen, then we will start to escavate. >> reporter: it will be taken for analysis. this isn't the first time authorities have followed a tip like this. >> there's been a lot of earth moved looking for the remains of jimmy hoffa, all negative so far. i mean, you're talking about digging up football stadiums and fields and backyards and basements. >> re